In a medium skillet, set over medium-high heat, add the olive oil. When hot, add the garlic clove. This will infuse the oil with the garlic. Add the sliced zucchini in one even layer and fry for 3 to 5 minutes. Some will get crispy and browned and others won’t. It’s all good either way. Transfer the zucchini to a paper towel or clean kitchen towel. Reserve a few of the crispy zucchini slices.
Bring a pot of water to a boil. When it reaches a boil, add a few pinches of salt. It might boil up a bit so beware. Add the spaghetti (or pasta of choice) and cook until al dente, about 9 minutes. Reserve 1 cup of pasta water and set aside. Drain the pasta.
Meanwhile, in a mason jar, using an immersion blender, add the zucchini, pecorino romano, parmesan, about 1/4 cup of pasta water, and a handful of basil leaves. Pulse until very smooth. Give it a taste and adjust the salt to your liking. If it needs more pasta water, don't be shy to add a splash or two.
Add the drained pasta to a bowl. Top it with the sauce, a few rounds of black pepper and a handful of torn basil leaves. Give it a mix and add a splash of pasta water to loosen it up even more. Toss until thoroughly combined. Divide amongst bowls and top with a few more basil leaves and the reserved zucchini slices.